PGI User's Guide

Run-time Library RoutinesRun-time Library Routines with Examplesomp_set_num_threadsSets the number of threads to use for the next parallel region.This subroutine or function can only be called from a serial region of code. If it is called fromwithin a parallel region, or from within a subroutine or function that is called from within a parallelregion, the results are undefined. Further, this subroutine or function has precedence over theOMP_NUM_THREADS environment variable.FortranC/C++omp_get_thread_numsubroutine omp_set_num_threads(scalar_integer_exp)void omp_set_num_threads(int num_threads);Returns the thread number within the team. The thread number lies between 0 andomp_get_num_threads()-1. When called from a serial region, this function returns 0. A nestedparallel region is the same as a single parallel region.FortranC/C++integer function omp_get_thread_num()int omp_get_thread_num(void);omp_get_ancestor_thread_numReturns, for a given nested level of the current thread, the thread number of the ancestor.FortranC/C++omp_get_active_levelinteger function omp_get_ancestor_thread_num(level)integer levelint omp_get_ancestor_thread_num(int level);Returns the number of enclosing active parallel regions enclosing the task that contains the call. PGIcurrently supports only one level of active parallel regions, so the return value currently is 1.FortranC/C++omp_get_levelinteger function omp_get_active_level()int omp_get_active_level(void);Returns the number of parallel regions enclosing the task that contains the call.FortranC/C++omp_get_max_threadsinteger function omp_get_level()int omp_get_level(void);Returns the maximum value that can be returned by calls to omp_get_num_threads().If omp_set_num_threads() is used to change the number of processors, subsequent calls toomp_get_max_threads() return the new value. Further, this function returns the maximum valuewhether executing from a parallel or serial region of code.FortranC/C++integer function omp_get_max_threads()void omp_get_max_threads(void);66